Method and centrifuge for dewaxing oil solution



April 3, 1951 G. H. ANDERssoN 2,547,612

METHOD AND CENTRIF'UGE FOR IDEWAXING OIL SOLUTION Filed Oct. 17, 1945 0% Arm/Mins.

Patented Apr. 3, `1951 Y METHOD AND CENTRIFUGE FOR DEWAXING on. SOLUTION Gustav Harry Andersson, Smedslatten, Sweden,

assignerl to Aktiebolaget Separator-Nobel,

Stockholm, Sweden, a corporation of Sweden Application October 17, 1945, Serial No. 622,806

In Sweden October 20, 1944 Claims. l

Wax can be removed from lubricating oil by rst chilling the oil and then centrifuging saine in a separator, the wax thus being precipitated and separated. It may thereby be of advantage to add a heavy solvent before the chilling, the wax thereby being obtained at the separation as the lighter component which can be collected and discharged at the center of the separator bowl. The centrifuge bowls which hitherto have been employed for the separation were constructed in such a manner that the mixture of wax particles and oil solution entered the separating chamber of the centrifuge bowl at one end of the chamber, whereas the two outlets for the separated components were located at the other end of the separating chamber. venience that the centrifuge bowl is rapidly clogged whentrying to obtain a wax as free from oil as possible.

This inconvenience is eliminated when the separated wax, according to the present invention, is discharged at that end of the separating room of the centrifuge bowl Where the mixture is introduced. The principal difference between the centrifuges used up to the present and a centrifuge according to the invention is illustrated in the drawing, in which Fig. 1 is a schematic view of a bowl which, at the left side, illustrates a type used up to the present, and at the right side a construction according to the invention, and

Fig. 2 is a vertical sectional view of a centrifuge made in accordance with the invention.

Referring first to the left side of Fig. 1, showing the prior type of bowl, the mixture of wax particles and oil solution enters the bowl through the tube I and flows through a number of radial tubes into the part 2 of the separating chamber. The separated wax is concentrated in the inner part 3 of the separating chamber and is discharged through the level outlet 4. The waxfree solution of oil `and heavy solvent leaves the bowl through a number of channels 5. The Wax particles are of different size. The bigger ones which are the most easy to separate move from the part 2 principally towards the centre of the bowl, whereas the smaller particles, when moving towards the centre, simultaneously also move to the level outlet Il. In this way big particles accumulate after some time at the lower end of 50 This involves the ineen- The construction shown in the right half of the ligure according to the present invention does not involve any accumulation of wax. The separating liquid passes through a number of channels to the part 6 at the upper side of the separating chamber, from which part the bigger wax particles move rather directly towards the centre of the centrifuge bowl under the influence of the centrifugal force. There they can however immediately leave the separating chamber over the adjacent level outlet 4. The smaller wax particles, the rising velocity of which is not as high, are pushed aside by the bigger ones and are forced to move approximately along the way l' as shown in the figure. However, it does not involve any inconvenience that these smaller particles towards the centre at a greater distance from the level outlet 4, since these particles, 'together with the remaining oil solution, form a more movable mass than the bigger particles. Whendisplayed towards the centre, they can thus move in axial direction towards the level outlet Il. The location of the inlet and the wax outlet thus prevents the bowl from clogging, and simultaneously a better drying of the wax is obtained. The said location of the inlet and the wax outlet in relation to each other also involves another advantage. At the arrangement according to the left half of Fig. 1, the outlet 5 for the oil solution must be placed at the opposite end to the part 2 of the separating chamber, since a great accumulation of wax in the part 2 must be reckcned with. The outlets for the two components will then be at the same end of the centrifuge bowl, which is a disadvantage owing to the risk of the components being re-mixed in case of leakage. According to the right half of Fig. 1, however, the outlet 8 can be placed without any inconvenience at the opposite end to the wax outlet, whereby this risk is eliminated.

Fig. 2 shows diagrammatically a separator according to my invention. The liquid mixture to be separated is fed to the separating chamber or locus of centrifugal force 2 at 2at through thecentral tube I. The separated wax is collected in the inner part 3, leaves the separating chamber over the level outlet il and flows into the paring chamber S, from which it is pared off by means of the paring tube i0. This should work at so large a diameter that the level in the paring chamber 9 does not reach the level outlet 4. It is in fact desirable that the liquid equilibrium in the bowl is as good as possible, and this is ensured by removing the oil solution from the bowl in the way shown in said ligure. Through the channel 8 the 3 oil solution flows into the paring chamber I I, from which it is removed by means of the paring tube I2, the cutting edge I3 of which is a straight line of large extension in the direction of the rotation axis. For this reason the liquid level in the paring chamber Ii will have a determinate position, independent of the throughput capacity. The level in the paring chamber can be regulated during Work by making the paring tube I2 movable. If such a paring tube is arranged for the oil solution and the large level outlet 4 is used for' the wax, the bowl will be quite insensible to variations of the mixing proportions in the liquid under separation. It is of course desirable thatV the resistance in the paring tube is as low as possible so that no accumulation occurs in its orice, whereby the liquid level in the paring chamber would be displaced. For this reason the paring tube I2 is made as short as possible and, although this is not shown in the drawing, it may be advisable to make the paring tube end directly above the outlet I4 from the collecting tank I5 which surrounds the paring chamber and in which the sprinkles from the latter are collected and discharged together with the main part of the liquid. It is more advantageous to use a paring tube here instead of a paring disc and a pressure regulating device, because the paring tube requires less effect and besides maintains the position of the liquid level more constant.

When the separator bowl has tobe removed from the spindle for cleaning, the paring tube I2 is put into such a position that the bowl can be lifted off. In order to prevent this from being forgotten, whereby the paring device could be damaged, a locking device for the hood IG is directely connected with an operating device for the paring tube I2. More particularly, a wheel or knob Il is mounted on the outer end of a slidable shaft I'la which, at its inner end, is rigidly connected to the paring tube I2, as by means of a collar I'Ib fixed to the shaft and surrounding the tube. The shaft IIa is bent at IIc so that it extends with a clearance around one side of the neck 29a of an underlying plate 29, the neck surrounding the bowl spindle 3Q. The clearance provided at Il allows shaft I'Ia and tube I2 to be moved to the right by knob II for a sufficient distance to cause the parer edge I3 to overlie the opening or clearance space IIa in the. bottom of paring chamber II, whereby the bowl may be lifted from spindle 30 without striking the paring tube I2. An arm I9 is pivotally connected to knob I'I and is mounted intermediate its endsv on a pivot I8. At its free upper end, the arm I9 has a portion -I 9B overlying a projection 20. on the hood I6, the parts I9a and 20 forming a locking device having a connection I9, I'Ia to the parer tube I2. Accordingly, the hood cannot be lifted to obtain access to the bowl as long as knob I'I is in its outer position, in which the parer `edge I3 is in its operative position over the bottom of chamber II. However, when knob I'I' is moved inwardly to displace the parer edge I3 to the right, asY previously described, the arm portion ISa swings to the left to allow hood I6 to be lifted. Thus, it is certain that the parer I2 cannot be damaged when lifting up the bowl. The arm I9 is provided with a pointer 2|, indicating on a scale 22 the position of the paring tube.

The overflow liquid leaving the central inlet part 23 through the opening 24 in case of the separator bowl being clogged or of too high a feed rate, must not be mixed with any of the components. A separate chamber 25 for overflow liquid has therefore been arranged between the separating chamber and the paring chamber 9 for the wax. The chamber 25 has an outlet 2 5a through which the overflow liquid discharges into the hood chamber I6a, as indicated by the arrows. Any overflow from the paring chamber 9 will discharge over the edge of the top opening in charnber 9 and then outwardly into chamber I6a as shown by the upper horizontal arrow. The overflow collected in chamber IIial flows through an opening in the bottom of chamber I6a into a recess SI2 in the centrifuge frame SI, and then down through a pipe 32 into a receptacle 33. There is likewise a safety chamber 28, provided with an outlet 2, between the collecting tank I5 for the oil solution and the chamber 26 containing the driving device of the separator, whereby the liquid to be separated is prevented from penetrating into the chamber 26 in case of overflow down through the space between spindle 30- and the neck 292L of plate 29.

The embodiment of the separator above described should of course only be considered as an example, since the construction may be varied in its details without evading the idea of the invention.

I claim:

l. A process for continuously separating wax from a mixture of wax' and an oil solution heavier than the wax, which comprises feeding the mixture directly into one end of a centrifugal separating chamber, displacing the larger wax particles of the mixture toward the axis of the chamber while retaining at least a major portion of said said particles near said end of the chamber, discharging the centrifugally separated wax, including said major portion of the larger particles, only from said end ofthe chamber, whereby the major portion of said larger particles are maintained near said end of the chamber from their entrance into the locus until their discharge therefrom, and separately discharging. the oil solution from the chamber.

2. A process asv defined in claim 1, in which the centrifugally separated oil solution is discharged from the chamber at the end thereof opposite said rst end.

3. In a centrifuge adapted especially for separating wax from a mixture of wax and an oil solution heavier than the wax, a centrifugalbowl comprising a separating chamber and an inlet for the mixture opening directly into one end of the separating' chamber, the chamber having also at said end a level outlet for the wax through which wax particles are movable directly from near said end of the chamber, said level outlet being concentric to the bowl axis and located in an end wall of the chamber, the chamber having at its opposite end an outlet for theseparated oil solution.

4. A centrifuge as defined in claim 3, comprising also a paring tube for removing the separated oil solution from the bowl, and means for adjusting the paring tube radially of the bowl axis.

5. A centrifuge as defined in claim 3, comprising also means on the bowl providing a paring chamber for receiving separated oil solution from the separating chamber, there being an opening in one wall of the paring chamber to provide a clearance space, a stationary collecting tank surrounding the paring chamber and having an outlet, the tank being adapted to collect sprinkles passing from the paring chamber through said clearance space, and an adjustable paring tube having its inlet end in the paring chamber and its outlet end in the collecting tank.

6. A centrifuge as defined in claim 3, comprising also means on the bowl providing a paring chamber for receiving separated wax discharged from the separating chamber through said level outlet, and a paring tube having its inlet end located in the wax paring chamber at a substantially greater radius from the axis of rotation than said level outlet, whereby the flow of wax through the level outlet is undisturbed.

7. A centrifuge as defined in claim 3, comprising also means on the bowl providing at the top and at the bottom thereof paring chambers for the separated wax and the separated oil solution, respectively, a paring tube disposed in each of the paring chambers and extending through a central opening in a wall ci its paring chamber, and a pair of stationary collecting tanks having separate outlets, one tank surrounding each of the paring chambers and adapted to collect sprinkles passing from the adjacent paring chamber through said central opening.

8. In a centrifuge comprising a frame, a spindle in the frame, a centrifugal bowl removably mounted on the spindle, and a hood on the frame normally covering the bowl but movable to uncover the bowl and thereby permit its removal from the spindle, the combination of a paring tube extending into the bowl and movable between a paring position overlying part of the bowl and an inoperative position permitting said removal of the bowl, a locking device for securing said hood against movement to uncover the bowl, and a connection between the paring tube and the locking device for rendering said device inoperative in response to movement of the paring tube to its inoperative position.

9. A centrifuge according to claim 8, in which said connection includes a slidable shaft extending through the frame and operable from outside the frame to adjust the position of the par'- ing tube, and an arm connecting the shaft to the locking device and responsve to movements of the shaft.

10. A centrifuge according to claim 3, comprising also a stationary frame surrounding the bowl, a hood movably mounted on the frame over the bowl and having a collecting chamber, means on the bowl providing a chamber for receiving overow from said inlet and having an outlet communicating with said collecting chamber, and means on the bowl providing a paring chamber for receiving separated wax discharged from the separating chamber through said level outlet, said paring chamber having an overflow opening communicating with the collecting chamber.

GUSTAV HARRY ANDERSSON.

REFERENCES CITED rl-he following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 347,702 Evans Aug. 17, 1886 463,058 Laidlaw Nov. 10, 1891 732,886 Odell et al. July 7, 1903 810,975 Petersen Jan. 30, 1906 837,403 Hedderick Dec. 4, 1900 884,830 Lindahl Apr. 14, 1908 2,052,124 Andersson Aug. 25, 1936 2,106,964 Wells Feb. 1, 1938 2,111,508 Jones Mar. 15, 1938 2,197,911 Andersson Apr. 23, 1940 2,261,394 Lindgren Nov. 4, 1941 2,289,431 Jung July 14, 1942 FOREIGN PATENTS Number Country Date 9,833 Great Britain Apr. 25, 1912 23,318

Australia Apr. 23, 1936 

1. A PROCESS FOR CONTINUOUSLY SEPARATING WAX FROM A MIXTURE OF WAX AND AN OIL SOLUTION HEAVIER THAN THE WAX, WHICH COMPRISES FEEDING THE MIXTURE DIRECTLY INTO ONE END OF A CENTRIFUGAL SEPARATING CHAMBER, DISPLACING THE LARGER WAX PARTICLES OF THE MIXTURE TOWARD THE AXIS OF THE CHAMBER WHILE RETAINING AT LEAST A MAJOR PORTION OF SAID PARTICLES NEAR SAID END OF THE CHAMBER, DISCHARGING THE CENTRIFUGALLY SEPARATED WAX, INCLUDING SAID MAJOR PORTION OF THE LARGER PARTICLES ARE TICLES, ONLY FROM SAID END TO THE CHAMBER, WHEREBY THE MAJOR PORTION OF SAID LARGER PARTICLES ARE MAINTAINED NEAR SAID END OF THE CHAMBER FROM THERE ENTRANCE INTO THE LOCUS UNTIL THEIR DISCHARGE THEREFROM, AND SEPARATELY DISCHARGING THE OIL SOLUTION FROM THE CHAMBER.
 3. IN THE CENTRIFUGE ADAPTED ESPECIALLY FOR SEPARATING WAX FROM A MIXTURE OF WAX AND AN OIL SOLUTION HEAVIER THAN THE WAX, A CENTRIFUGAL BOWL COMPRISING A SEPARATING CHAMBER AND AN INLET FOR THE MIXTURE OPENING DIRECTLY INTO ONE END OF THE SEPARATING CHAMBER, THE CHAMBER HAVING ALSO AT SAID END A LEVEL OUTLET FOR THE WAX THROUGH WHICH WAX PARTICLES ARE MOVABLE DIRECTLY FROM NEAR SAID END OF THE CHAMBER, SAID LEVEL OUTLET BEING CONCENTRIC TO THE BOWL AXIS AND LOCATED IN AN END WALL OF THE CHAMBER, THE CHAMBER HAVING AT ITS OPPOSITE END AN OUTLET FOR THE SEPARATED OIL SOLUTION. 